The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > All 4x4 Tech & Off Roading

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-06-2011, 08:01 PM   #1
dave666693
Registered User
 
dave666693's Avatar
 
Join Date: Jul 2005
Location: Edgewood, WA
Posts: 899
front and rear end gears??

I am putting together an off road/urban crawler type Blazer. Since it is road and off road I am thinking about 3:73 gears with posi front and rear. 35" tires and a 383 stroker. Plenty of torque I am guessing for the 3:73 gears. What do you guys think?
__________________
67 C20/
68 C10 stepside/inline 250--current project
71 GMC 4x4
70 Blazer project-Zombie assault vehicle
67 4x4 Burb
dave666693 is offline   Reply With Quote
Old 04-06-2011, 09:08 PM   #2
Zoomad75
K5Camper
 
Zoomad75's Avatar
 
Join Date: Mar 2004
Location: Pueblo, CO
Posts: 1,513
Re: front and rear end gears??

I'm running 35's with 3.73's in my K5 and I'd go a little deeper in the gearing department. Granted, my little 350 is of unknown age and tired, but even with more power your loosing a lot of that torque just getting the 35's rolling. 35's and 3.73's is roughly similar to 33's with 3.42's. 35's really are best with minimum 4.10's or 4.56's. Since you are seeing some street time, 4.10's should give you the best of both worlds.
__________________
Rob Z.
1975 K5 350/465/205/D44/12b 4" lift on 35's- RIP
1991 K5 8.1L/NV4500/241/D44/14b FWC Camper
Zoomad75 is offline   Reply With Quote
Old 04-06-2011, 09:08 PM   #3
Your41Plague12
Registered User
 
Your41Plague12's Avatar
 
Join Date: Dec 2010
Location: Pittsburgh, PA
Posts: 1,009
Re: front and rear end gears??

For 35's I'd go 4.30 or 4.56 for the gears. That will move the tires pretty well!
__________________
Steve
Member of the Foot Pedal Club
'83 Chevy K20: 6" Rough Country, 3" Performance Accessories BL,
Bushwacker Cutouts, 38x15.50 Mickey Thompson Baja Claws,
350 HP 350 crate engine from Jegs, Turbo 400
Your41Plague12 is offline   Reply With Quote
Old 04-07-2011, 03:12 AM   #4
MTCK
Registered User
 
MTCK's Avatar
 
Join Date: Dec 2009
Location: Fairbanks, AK
Posts: 1,830
Re: front and rear end gears??

How old is the blazer? What trans are you running? If you have a 700R4 my vote is for 4.56's, if no OD then 4.10. The 208/241's have a deeper low range, which is nice if it is a later model truck.
__________________
-Marcus

1991 V3500 L29 454 4L80E NP205 D60/14 Bolt 4.56's
1984 K30 292 TH400 NP205 D60/14 Bolt 4.56's flat bed 7'6" Meyer Plow
2022 Silverado 3500 L8T
Project Daily Driver
Project Heavy Hauler
Project Plow Truck
MTCK is offline   Reply With Quote
Old 04-07-2011, 09:08 AM   #5
dave666693
Registered User
 
dave666693's Avatar
 
Join Date: Jul 2005
Location: Edgewood, WA
Posts: 899
Re: front and rear end gears??

Quote:
Originally Posted by MTCK View Post
How old is the blazer? What trans are you running? If you have a 700R4 my vote is for 4.56's, if no OD then 4.10. The 208/241's have a deeper low range, which is nice if it is a later model truck.
It's a 71 Blazer. Probably going to run a TH350 trans.
__________________
67 C20/
68 C10 stepside/inline 250--current project
71 GMC 4x4
70 Blazer project-Zombie assault vehicle
67 4x4 Burb
dave666693 is offline   Reply With Quote
Old 04-07-2011, 09:59 AM   #6
Torrey72
Rollin in my K5 toaster
 
Torrey72's Avatar
 
Join Date: Oct 2010
Location: Pacific Northwest
Posts: 254
Re: front and rear end gears??

Here is a gear/tire calculator http://www.4lo.com/4LoCalc.htm
This will help you find a cruising rpm you and your truck can live with.
Posted via Mobile Device

Edit: BTW 488 is what I like with 35s. But my Blazer is more of an around town street and off road weekend toy. Not a daily driver. Also, I'd go with an electric locking front. Not all time posi. Full time up front makes it a bear to steer when you need it but 5% of your off road driving. Detroit lockers are my fav for the rear.

Last edited by Torrey72; 04-07-2011 at 10:10 AM.
Torrey72 is offline   Reply With Quote
Old 04-07-2011, 02:16 PM   #7
dave666693
Registered User
 
dave666693's Avatar
 
Join Date: Jul 2005
Location: Edgewood, WA
Posts: 899
Re: front and rear end gears??

so what front and rear end should a guy be looking for? Dana 60 and 44 with 4:11's and posi? What posi or locker from our era is the one to get?
__________________
67 C20/
68 C10 stepside/inline 250--current project
71 GMC 4x4
70 Blazer project-Zombie assault vehicle
67 4x4 Burb
dave666693 is offline   Reply With Quote
Old 04-07-2011, 02:55 PM   #8
sandking
.....I am working on it.....
 
sandking's Avatar
 
Join Date: Jul 2007
Location: Anaheim Hills, Ca
Posts: 960
Re: front and rear end gears??

Srew the gear ratio, lets see the Blazer!!!!
For me, I have 35's and the stock 3:73 gears front and rear, but I have not driven it yet. Mine will also be on and off road. I looked at it this way, get it on the road and then upgrade later
__________________
.
.
.
.
.
View my build thread HERE
sandking is offline   Reply With Quote
Old 04-07-2011, 02:55 PM   #9
Altec
Getcha Pull
 
Altec's Avatar
 
Join Date: Nov 2010
Location: MD
Posts: 691
Re: front and rear end gears??

So you are running a 383 through a th350 with 35's? How fast do you plan on driving on the high way, and what sort of off roading do you plan to be doing?
__________________
'81 K10 454/SM465
'86 S10 Blazer
'95 H-D Softail
'96 Integra
Altec is offline   Reply With Quote
Old 04-07-2011, 04:32 PM   #10
dave666693
Registered User
 
dave666693's Avatar
 
Join Date: Jul 2005
Location: Edgewood, WA
Posts: 899
Re: front and rear end gears??

Quote:
Originally Posted by Altec View Post
So you are running a 383 through a th350 with 35's? How fast do you plan on driving on the high way, and what sort of off roading do you plan to be doing?
normal city and highway driving. 65 mph max

offroading would be mud holes and trails.
__________________
67 C20/
68 C10 stepside/inline 250--current project
71 GMC 4x4
70 Blazer project-Zombie assault vehicle
67 4x4 Burb
dave666693 is offline   Reply With Quote
Old 04-07-2011, 04:59 PM   #11
Altec
Getcha Pull
 
Altec's Avatar
 
Join Date: Nov 2010
Location: MD
Posts: 691
Re: front and rear end gears??

Well, at 65-tops I think a 4.10 is the way to go. Trying to factor in things like transmission slip, and such I think that will put you at a decent middle of the road. If you don't mind nipping at the heals of 3000RPM at 65MPH then 4.33 is the next best option.
__________________
'81 K10 454/SM465
'86 S10 Blazer
'95 H-D Softail
'96 Integra
Altec is offline   Reply With Quote
Old 04-07-2011, 05:27 PM   #12
Torrey72
Rollin in my K5 toaster
 
Torrey72's Avatar
 
Join Date: Oct 2010
Location: Pacific Northwest
Posts: 254
Re: front and rear end gears??

Quote:
Originally Posted by Altec View Post
Well, at 65-tops I think a 4.10 is the way to go. Trying to factor in things like transmission slip, and such I think that will put you at a decent middle of the road. If you don't mind nipping at the heals of 3000RPM at 65MPH then 4.33 is the next best option.
+1
I bet anything over 4.10 is going to bother you as for how much you would be revving the crap out of the engine. If you travel often on the freeway, 3,000 rpm starts to feel like your abusing your engine. I have 4.56s in my jeep with 35s and I have to drive under 60 on the freeway or the 401 will start overheating. it is fun off road but not so much if I need to go places. How you build the 383 in regards to its usable power output plays a factor as well.

Dave, we really can't give you a description of the perfect setup. That is kind of an individual preference. It is almost like us picking what music you should listen to. For instance, you can keep the Dana 44s and funky stock steering set up. if you're into the factory look. Or on a budget. Or you could , say, put a Dana 60 up front with crossover steering and a 14 bolt FF in the rear. complimented with disk brakes on all four corners. As another example.
When looking for axles to buy. It is easier to buy the axles you want under the truck as is. Then pick and choose all the goodies you plan on putting inside them separately. IMHO, But my opinion isn't that valuable.

And like SandKing said... Lets see a picture of this blazer!
Torrey72 is offline   Reply With Quote
Old 04-07-2011, 07:17 PM   #13
orbot
Registered User
 
orbot's Avatar
 
Join Date: Jan 2008
Location: Chula Vista, Ca
Posts: 518
Re: front and rear end gears??

I run a 383/th350 with 33"s and 4.10 myt truck is a bit heavy cause of the tubing and stuff but it drives ok on the road although at high speeds people say it does sound loud like it needs one more gear... so you might be ok with the 4.27's cause you kill the 350 tranny at high speeds.
orbot is offline   Reply With Quote
Old 04-07-2011, 07:23 PM   #14
Torrey72
Rollin in my K5 toaster
 
Torrey72's Avatar
 
Join Date: Oct 2010
Location: Pacific Northwest
Posts: 254
Re: front and rear end gears??

Have you considered a 700r4? It's a 4 speed overdrive automatic.
Torrey72 is offline   Reply With Quote
Old 04-07-2011, 08:06 PM   #15
dave666693
Registered User
 
dave666693's Avatar
 
Join Date: Jul 2005
Location: Edgewood, WA
Posts: 899
Re: front and rear end gears??

I have 4.10's in my 3/4 ton pick-up with 31" tires. It has a strong 350. At 65 it drives fine. I am guessing 4:10's is the way I will go with some kinf of limited slip in the rear and a locker in the front. I have a good deal available for a front and rear end with 3:73's, but the 35" tires would be a problem I think.
__________________
67 C20/
68 C10 stepside/inline 250--current project
71 GMC 4x4
70 Blazer project-Zombie assault vehicle
67 4x4 Burb
dave666693 is offline   Reply With Quote
Old 04-07-2011, 10:03 PM   #16
orbot
Registered User
 
orbot's Avatar
 
Join Date: Jan 2008
Location: Chula Vista, Ca
Posts: 518
Re: front and rear end gears??

Quote:
Originally Posted by dave666693 View Post
I have 4.10's in my 3/4 ton pick-up with 31" tires. It has a strong 350. At 65 it drives fine. I am guessing 4:10's is the way I will go with some kinf of limited slip in the rear and a locker in the front. I have a good deal available for a front and rear end with 3:73's, but the 35" tires would be a problem I think.
Wouldnt it be the other way around, locker in the rear and a limited slip up front...
orbot is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:16 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com